Cover plate

ABSTRACT

A container for transport or storage of liquid in bulk having a filling opening defined by an upstanding neck, the combination of a cover plate having a depending flange, by which the cover plate, when in position, is located on said neck, interlocking means for positively securing the cover plate to the neck including annular seating surfaces formed respectively on the neck and flange of the cover plate, a plurality of circumferentially arranged balls for operative engagement with said seating surfaces and by which the cover plate is positively held in position thereon, an annular cage encircling the neck and by means of which the balls are normally held in their operative position, the cage being capable of displacement by which the balls can be withdrawn from their operative position to a release position to permit removal of the cover plate.

United States Patent 1 Platts et al.

[54] COVER PLATE [75] Inventors: Douglas John Platts, Worksop; KeithEllis Hunter, Sheffield, both ailin laaq.

[73] Assignee: General Descaling Company, Limited, Nottinghamshire,England 22 Filed: June28, 1971 21 Appl.No.: 157,111

[30] Foreign Application Priority Data [56] References Cited UNITEDSTATES PATENTS 11/1965 Sorensen ..220/55 R X 3/1936 Parker ..220/55 R X1 May8,1973

Gordon ..220/55 R X Drucker ..220/55 A X [57] ABSTRACT A container fortransport or storage of liquid in bulk having a filling opening definedby an upstanding neck, the combination of a cover plate having adepending flange, by which the cover plate, when in position, is'located on said neck, interlocking means for positively securing thecover plate to the neck in cluding annular seating surfaces formedrespectively on the neck and flange of the cover plate, a plurality ofcircumferentially arranged balls for operative engagement with saidseating surfaces and by which the cover plate is positively held inposition thereon, an annular cage encircling the neck and by means ofwhich the balls are normally held in their operative position, the cagebeing capable of displacement by which the balls can be withdrawn fromtheir operative position to a release position to permit removal of thecover plate.

Patented May 8, 1973 3,731,837

4 Sheets-Sheet l Patented May 8, 1973 4 Sheets-Sheet 2 Patented May 8,1973 I 3,731,337

4 Sheets-Sheet 5 COVER PLATE or lid for the filling opening of thecontainer or tank of the vehicle.

Most large capacity vehicles of this kind, whether it be a road vehicleor a rail wagon, are equipped with power actuated braking systems. Bothon starting and stopping a vehicle the resultant surge of liquid willcause an appreciable rise in pressure within the container, and inbringing it to a halt, especially should it be necessary to apply thebrakes suddenly as in an emergency, the increase in pressure may provehighly dangerous unless the cover plate is securely held in position andsealed. Therefore, it becomes all the more important that cover platesare not only fluid tight to prevent any escape of liquid or gas vaportherefrom in the case of petroleum and other volatile compounds, butshall be capable of withstanding high pressure without shifting.

According to the present invention, in a cover plate or the like havinga flange adapted to overlie the neck of a container opening and in whicha sealing ring is placed in position between the flange and neck, thereis provided interlocking means therefor comprising circumferentiallylocated balls for engagement when in the locked or closed position ofthe cover plate with angularly inclined seating faces formedrespectively on the said neck and flange portions, the balls beingretained in a cage by means of which they can be withdrawn from thelocked or closed position to a release position within an annular recessor recesses in the said fiange.

The arrangement has the advantage that any increase in pressure withinthe container tending to unseat the cover plate is transferred throughthe balls to the seating on the neck of the container opening. Inpractice the seating faces may be machined at an angle of 45, theseating on the neck of the container being formed as an undercutshoulder thereon and the seating on the flange of the cover plate beingextended to form an entrant wall to the recess into which the balls canbe withdrawn.

The invention is illustrated in the accompanying drawings, in which:

FIG. 1 is a sectional view of a cover plate;

FIG. 2 is a detailed plan view;

FIG. 3 is a transverse section of a cover plate constructed inaccordance with the invention but having means by which it is supportedfor lateral swinging movements when released;

FIGS. 4 and 5 are detail sectional views showing cam operated means foreffecting displacement of the ball cage when releasing the cover plate,and

FIG. 6 is a part sectional view showing a cover plate having an internalsealing plate.

Referring to FIG. 1, 1 indicates the shell of a container or acylindrical tank and 2 the neck or throat of a filling opening, 3 beingpart of a domed cover plate or lid.

The cover plate in accordance with this invention is retained in itsclosed position by a number of balls 4 mounted in openings in a cagedformed as a carrier ring 5, the ring 5 having laterally projectingbrackets 5' which, as shown in FIG. 2, are constructed in the form of ahandle by means of which the cover plate as a whole can be raised priorto being lifted off the neck when it is to be removed.

To facilitate lift off a similar bracket or handle 3 is provided on thecover plate or lid 3 so that the operator can apply pressure to thehandle 5' by gripping both handles.

It will be seen that the cover plate 3 has a depending flange 7 and thatboth the flange 7 and an external shoulder 8 on the neck are formed withseating faces 10 and 11, with which the balls 4 interlock. The seatingfaces 10 and 11 are similarly at an: angle (conveniently 45) to thevertical, being parallel or substantially parallel to one another andtherefore any upward lift, i.e. thrust, to which the cover plate 3 maybe subjected due to a rise of pressure in the tank or container 1 willbe transmitted from the seating face 10 through the balls 4 to theseating face 11 on the neck 2, thereby preventing it from movement, sothat the balls and their associated flanges function as inter-lockingmeans.

When it is desired to release the cover plate the cage 5 is raised, whenthe balls 4 will be forced outwardly until they are fully withdrawn intoan annular recess 12 in the flange 7, the side wall of the recess beingan extension of the seating 10.

To raise the cage 5 carrying the balls 4 the fingers are placed belowthe handle 5 at the: same time gripping the handle 3 on the lid 3 so asto apply pressure to force the ball cage upwardly.

The cover plate 3 is effectively sealed to the neck by a neoprenesealing ring 13of L-section, the cover plate being undercut so as toprovide a flat 14 on which the ring 13 is located, the horizontal limb15 of the ring projecting inwardly so as to overlie and make seal withthe flat provided by the upper side of the shoulder 8.

To limit the downward movement of the cover plate, stops in the form oflugs 17, either on the cover plate as shown or spaced circumferentiallyaround the neck 2, may be provided.

It will be seen that sufficient clearance is provided between the flange7 and the neck 2 to accommodate the carrier ring 5 and that its upperend engages beneath the tongue or limb 15 of sealing ring 13 so that onpulling the ring upwardly by means of its handles, the ring will breakthe seal at the same time as forcing the balls 4 into the recess 12,when the cover plate can be removed.

In large size tankers the weight of the cover plate is considerable andmay require several men to remove it. To assist in'its removal the coverplate may be spring assisted in an upwards direction. Furthermore,instead of removing it completely, provision may be made for swinging itclear of the opening and in one such 'arrangement the cover plate isslidably mounted on vertical pins 20, 21, as shown in FIG. 3. By makingthe one pin 20 longer than the other when the cover plate has beenlifted to a position where it is clear of the shorter pin it can beswung through about the long pin to expose the opening. This arrangementhas the advantage that the cover plate remains captive at all times.Sockets 22 are attached to the inside of the neck to receive the pins20, 21, the socket for the longer pin housing a compression spring 23.

In the arrangement shown in FIG. 1, when the ball cage or ring 5 israised it dislodges the sea] at the same time as unlocking the balls andby so doing it introduces a safety factor, inherent in the design, inthat should the internal pressure appreciably exceed the external(atmospheric) pressure, the upward thrust on the cover plate istransmitted via surface 10 through the balls to shoulder 11 so that anypull on the cage by the operator will be resisted. Thus the cage cannotbe lifted to unlock when a dangerous pressure exists in the vessel.

Provision may be made for releasing any excess pressure before removingthe cover plate, i.e. venting before unlocking. This may be done bymaking the cage holes in the form of vertical slots as shown in FIG. 3.In this way the cage may be given a small vertical movement withoutlifting the balls, this movement being sufficient to unseat the seal,thus blowing down may then continue in safety. The slot is soproportioned that the condition as in FIG. 1 is retained above the ballsso that cover pressure equates to ball locking as before.

It could occur that a slight carriage i.e. cage 5 lift for thisarrangement would require more lifting effort than available from simplehandles and some form of elementary jacking between parts 1 and 5 couldbe provided. For example, a pair of simple scroll cams could be mountedon parts 1 and 2 beneath the cage. They would take no part in normaloperation but if the cover could not be unlocked because of initialpressure (the desirable feature of the design) the ball cage could becammed upwards a controlled amount to permit blow down without risk ofrelease. The cams or equivalent mechanical advantage lift the cagesufficiently for the balls to be lifted into the right position. Furtherlifting by hand would release the closure in the normal way.

One arrangement embodying a lift cam is shown in FIGS. 4 and 5 in whichprovision is made for raising the ball cage 5 by means of a cammechanism. As shown a spindle 30 is rotatably mounted in a bearinghousing lug 31 attached to the container wall. Fast on one end of thespindle 30 is a cam element 32, the face of which underlies thehorizontal limb 25 of the cage. On the outer end of the spindle 30 is asquared boss 33 to receive a turn buckle or lever 34 by which the cam 32can be turned from the closed position shown in FIG. 4 to the openposition shown in FIG. 5, in which the ball cage 5 has been raised toforce the balls 4 into the recess 12. In practice the mechanism isduplicated on opposite sides of the neck opening. Clearly the amount oflift of the cage can be controlled merely by turning the lever 34through a greater or smaller angle to suit operating conditions.

Referring now to FIG. 6 of the drawings, the cover plate 3 has attachedto its underside a dish-shaped sealing disc 27 having a shouldered edge28 which when the cover plate is in position makes sealing contact withthe upper edge of the neck 2. Disc 27 is secured to the plate 3 by athreaded stud on the underside of the plate and a fixing nut 29. Byfitting a sealing disc 27 on the underside of the main cover plate 3 ithas the advantage of providing a trapped volume of vapor between itselfand the cover plate and thus of providing a ready and convenient meansfor the operator of testing the integrity of the outer seal.

In a particular use, the inner space between the cover plate and disc ismaintained at a small pressure. The existence of such pressure is apositive guarantee to the operator that moisture and contaminants havenot and cannot enter the interior chamber of the container beneath thesealing disc. In this particular case the interior chamber itself,although sealed, would not be pressurized.

While the embodiment is intended primarily for transport vehicles andhas been described in relation to such, it is equally applicable forsealing off static installations under pressure in the ordinary way. Itshould be understood also that the invention can be adapted to manholecovers and the like of oblong, elliptical and square plan formations. Itcan also be adapted to traditional side hinged cover plates or doors,where the latter swing upwards clamshell fashion.

A further advantage of the cover plate of this invention is that theoperative surfaces which require precision machining are protected fromthe weather in that they lie beneath the cover plate.

What is claimed is:

1. In a container for transport or storage of liquid in bulk having afilling opening defined by an upstanding neck, the combination of acover plate having a depending flange, by which the cover plate, when inposition, is located on said neck, and interlocking means for positivelysecuring the cover plate to the neck including annular seating surfacesformed respectively on the neck and flange of the cover plate, saidseating surfaces being angularly inclined relatively to the axis of saidopening, a plurality of circumferentially arranged balls for operativeengagement with said seating surfaces and by which the cover plate ispositively held in position thereon, an annular cage encircling the neckand by means of which the balls are normally held in their operativeposition, said flange having an annular recess to receive the balls, thecage being capable of displacement by which the balls can be withdrawnfrom their operative position to a release position within said annularrecess to permit removal of the cover plate.

2. A container as claimed in claim 1 in which the cover plate isprovided with a sealing ring of L-shaped section, the base of the Lhaving an inwardly projecting portion for engagement with a flat on theneck.

3. A container as claimed in claim 2 in which the neck is formed with anannular shoulder on the underside of which the seating surface for theballs is formed and with the upper side of which the sealing ringengages.

4. In a container for transport or storage of liquid in bulk having afilling opening defined by aneck thereon the combination of a coverplate having a dependent flange for engagement with the neck, a sealingring on the flange for engagement with the neck to seal the contentsagainst escape from the container, interlocking means for positivelysecuring the cover plate to the neck including seating surfaces formedrespectively on the flange and the neck and being similarly angularlyinclined to the axis of said opening, a plurality of balls diametricallyopposite sides of which abut said seating surfaces when in the closedposition of the cover plate, an annular cage encircling the neck bywhich the balls are maintained in their operative position to hold thecover plate against release, said cage being capable of displacement byvwhich the sealing ring is disengaged and the balls can be withdrawn fromtheir operative position to a release position within an annular recessin said flange to permit removal of the cover plate.

5. A container as claimed in claim 4 in which the sealing ring is ofL-shaped section, the horizontal limb of the L having an inwardlyprojecting portion for engagement with the neck.

6. A cover plate as claimed in claim 4 in which the cover plate isprovided with circumferentially spaced lugs for engagement with the neckby which it is located when in its closed position.

7. A cover plate as claimed in claim 4 wherein the cover plate ispivotally secured to the neck.

8. A cover plate as claimed in claim 7 in which the neck is formed withupstanding pins, one of which is 10. A cover plate as claimed in claim 8in which sockets are provided on the inside of the neck to receive thepins.

111. A cover plate as claimed in claim 4 comprising a cage havingelongated holes whereby the cover plate may be raised a distancesufficient to break the seal prior to withdrawal of the balls.

12. A container according to claim 4 in which the cage is provided witha handle for use when actuating the same to release the cover plate.

13. A container according to claim 4 in which a cam device is providedon the container for effecting release of the cover plate.

14. A container according to claim 4 in which an inner disc is securedto the underside of the cover plate, the disc having sealing engagementwith the neck.

15. A container according to claim 1 in which the cover plate and theannular cage are provided with handles.

1. In a container for transport or storage of liquid in bulk having afilling opening defined by an upstanding neck, the combination of acover plate having a depending flange, by which the cover plate, when inposition, is located on said neck, and interlocking means for positivelysecuring the cover plate to the neck including annular seating surfacesformed respectively on the neck and flange of the cover plate, saidseating surfaces being angularly inclined relatively to the axis of saidopening, a plurality of circumferentially arranged balls for operativeengagement with said seating surfaces and by which the cover plate ispositively held in position thereon, an annular cage encircling the neckand by means of which the balls are normally held in their operativeposition, said flange having an annular recess to receive the balls, thecage being capable of displacement by which the balls can be withdrawnfrom their operative position to a release position within said annularrecess to permit removal of the cover plate.
 2. A container as claimedin claim 1 in which the cover plate is provided with a sealing ring ofL-shaped section, the base of the L having an inwardly projectingportion for engagement with a flat on the neck.
 3. A container asclaimed in claim 2 in which the neck is formed with an annular shoulderon the underside of which the seating surface for the balls is formedand with the upper side of which the sealing ring engages.
 4. In acontainer for transport or storage of liquid in bulk having a fillingopening defined by a neck thereon the combination of a cover platehaving a dependent flange for engagement with the neck, a sealing ringon the flange for engagement with the neck to seal the contents againstescape from the container, interlocking means for positively securingthe cover plate to the neck including seating surfaces formedrespectively on the flange and the neck and being similarly angularlyinclined to the axis of said opening, a plurality of balls diametricallyopposite sides of which abut said seating surfaces when in the closedposition of the cover plate, an annular cage encircling the neck bywhich the balls are maintained in their operative position to hold thecover plate against release, said cage being capable of displacement bywhich the sealing ring is disengaged and the balls can be withdrawn fromtheir operative position to a release position within an annular recessin said flange to permit removal of the cover plate.
 5. A container asclaimed in claim 4 in which the sealing ring is of L-shaped section, thehorizontal limb of the L having an inwardly projecting portion forengagement with the neck.
 6. A cover plate as claimed in claim 4 inwhich the cover plate is provided with circumferentially spaced lugs forengagement with the neck by which it is located when in its closedposition.
 7. A cover plate as claimed in claim 4 wherein the cover plateis pivotally secured to the neck.
 8. A cover plate as claimed in claim 7in which the neck is formed with upstanding pins, one of which iselongated to provide a fulcrum for the cover plate and about which itcan be swung when lifted to a position in which it clears the short pin.9. A cover plate as claimed in any of claim 8 in which the upwardmovement of the cover plate is spring assisted.
 10. A cover plate asclaimed in claim 8 in which sockets are provided on the inside of theneck to receive the pins.
 11. A cover plate as claimed in claim 4comprising a cage having elongated holes whereby the cover plate may beraIsed a distance sufficient to break the seal prior to withdrawal ofthe balls.
 12. A container according to claim 4 in which the cage isprovided with a handle for use when actuating the same to release thecover plate.
 13. A container according to claim 4 in which a cam deviceis provided on the container for effecting release of the cover plate.14. A container according to claim 4 in which an inner disc is securedto the underside of the cover plate, the disc having sealing engagementwith the neck.
 15. A container according to claim 1 in which the coverplate and the annular cage are provided with handles.